According to World's Metrological Organization, CO2 concentration in the atmosphere have reached to 403.3 ppm (parts per million) by the end of 2016 which is around 45% above the preindustrial levels. (the critical level is 400 ppm). Also, according to the world's health organization (WHO) in 2017 air pollution, mainly due to CO2 emissions, is causing more than 9 million deaths every year whereby trillions of $ are spent/lost to treat hospitalize effected people from said air pollutions around the world mainly in China and India.
There is increasing scientific evidence that global warming is caused by humans and made mainly by CO2 emissions into the atmosphere, which is the culprit of climate change worldwide. There has been many proposals and solutions in scientific literature and NASA top scientists research. Some are fantastic, however, like bringing 16 billion small reflecting mirrors into the stratosphere by space rockets to reflect sun light from coming to earth and thus reduce global warming, others more dramatic in which rockets would injecting SO2 into the atmosphere in order to reflect sun light whereby the ozone layer might be damaged by SO2. Still another solution propose that some millions of artificial trees are installed into open space in which Natrium hydrocarbonate (NaOH) is placed in the artificial “leaves” structures to capture CO2 that is then stored deep into the sea ground. The storage of CO2 in deep geological porous rocks, kilometres deep into seafloor has proven to be instable and more CO2 can significantly leak out into the atmosphere again. Another solution is to create artificial clouds by sending a fleet of some 40.000 unmanned vessels into the oceans that spray seawater particles into the atmosphere—by vertical-axis tidal currents—whereby clouds reflect sun light. Still another solution proposes that huge amounts of nitrogen granulates, a fertilizer (iron sulphate) is to be injected into deserted oceans in order to stimulate the growth of phytoplankton which can absorb much of the CO2 present in the atmosphere. However, iron sulphate, in some cases, might kill a lot of fish. All these solutions may result in huge environmental impact and not necessarily a positive one and are most likely unworkable or has too big of a risk and/or collateral damage; besides it would cost billions.
Therefore, an effective solution is still required to reduce or prevent CO2 emissions, such as minimizing CO2 emissions at its source, i.e inside smoke stacks and/or exhaust pipes, before it is out in the atmosphere and at reasonable costs.